In the gastrointestinal mucosa, cell migration plays a crucial role in the organization and maintenance of tissue integrity but the mechanisms involved remain incompletely understood. The objective of this proposal is to elucidate the signal transduction pathways that mediate GPCR-induced migration and restitution in intestinal epithelial cells. The non-receptor tyrosine kinase p125 focal adhesion kinase (FAK) localizes to multimolecular complexes that attach to the extracellular matrix, called focal adhesions. Immortalized cell lines derived from FAK-/- mice show decreased rate of migration but these cells have accumulated abnormalities and are fibroblastic rather than epithelial cells. Consequently, the precise role of FAK in cell migration and morphology of intestinal epithelial cells remains poorly understood. The central hypothesis to be explored in this proposal is that FAK plays a critical role in GPCR- induced cellular migration in intestinal epithelial cells. We will test this hypothesis by pursuing the following specific aims: 1) Define the role of FAK and Pyk2 in mediating cell migration in undifferentiated and differentiated intestinal epithelial cells.2) Characterize the role of FAK in mediating cytoskeletal organization in intestinal epithelial cells.3) Characterize migration and cytoskeletal organization of undifferentiated and Cdx2-differentiated IEC-18 cells expressing wild type, dominant-negative and mutant FAK. [unreadable] [unreadable] [unreadable]